Article ID: 2482426 - View products that this article applies to.
Consider the following scenario:
This issue occurs because the PR_USER_X509_CERTIFICATE property is formatted incorrectly in the nickname cache in the scenario that is described in the “Symptoms” section.
To fix this problem, install the following cumulative update:
(http://support.microsoft.com/kb/2505930/ )Description of the update for the Live Meeting Conferencing Add-in for Outlook: February, 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.